It would have been easy for Sen. Kirsten Gillibrand (D-N.Y.) to rest on her laurels at the town hall she held at Hudson Valley Community College in Troy, New York, on Wednesday. In the wake of the narrow defeat of the Republican "skinny repeal" of the Affordable Care Act, she received two standing ovations from a packed house before she even began to speak. (It seems unlikely that the senators who went down with Mitch McConnell's ship, like Dean Heller and Jeff Flake, would get a similar reception.) But she had a more ambitious agenda in mind. Before taking questions, she celebrated the defeat of ACA repeal but quickly observed that it was not enough: Too many people still couldn't afford insurance. And making a point she would return to repeatedly for the next hour, she identified her preferred solution: Medicare for all.

I have no idea if Gillibrand is running for president or what her chances of winning the Democratic nomination would be if she does run. But it is becoming increasingly clear that the 2020 Democratic nominee will support Medicare for all or a similar program as the ultimate goal for health-care reform, even if it's not Gillibrand or longtime single-payer advocate Bernie Sanders. And on Wednesday Gillibrand made the case for the policy very effectively.

As a public speaker, Gillibrand's effect is that of the happy warrior. She projects optimism and determination even when decrying the damage President Trump has done to American institutions or the many negative effects of Citizens United. There is a place for anger in political discourse, too, and I don't know what the most effective tone for the next Democratic nominee would be. But in the context of defending Medicare for all, Gillibrand's approach was very effective, making universal public insurance seem like common sense — which of course it is.

In her opening comments, Gillibrand identified the problem: A system based largely around for-profit insurance simply cannot provide access to health care that is both affordable and universal. It's not a coincidence that the United States, which relies on the market for health insurance more than any other advanced liberal democracy, also spends far more money despite being the only system that does not provide universal coverage. The ACA's historic expansion of Medicaid was a major step in the right direction, and the more regulated and subsidized insurance markets it established were a significant improvement on the status quo. But ultimately, health-care reform should build on the former rather than on the latter.

Some observers will take Gillibrand's emphasis on Medicare for all as a sign she intends to run for president in 2020. She might, but, as she herself pointed out, her position isn't new. Gillibrand also favored Medicare for all in her first House race in 2006, running in a congressional district George W. Bush had carried by 8 points two years earlier. Her support for Medicare for all wasn't the reason she won in an electoral context that was unusually favorable to the Democratic Party, but it also suggests that there's no reason to think the position would be a political liability for a Democratic presidential nominee either.

While the audience was generally supportive of her advocacy for Medicare for all — some scattered booing aside — one audience member asked a practical question: What should Congress do if the votes in Congress for Medicare for all aren't there yet? Gillibrand had a ready answer: "You get to single-payer by letting people buy in [to Medicare] now."

The revival of the public option Gillibrand advocated as an interim step is definitely gaining momentum, among both Democratic politicians and liberal public intellectuals. Sen. Sherrod Brown (D-Ohio) — another potential 2020 contender — and six colleagues recently co-sponsored a proposal introduced by Sen. Debbie Stabenow (D-Mich.) to create a Medicare buy-in for people 55 or over, an idea that was narrowly defeated during deliberations over the ACA. And in addition to making buy-ins to Medicare available to as wide a group as is politically feasible, it's also worth considering the proposal made by Gerard Anderson, Jacob Hacker, and Paul Starr to make Medicare available when exchanges offer fewer than two plans.

Voluntary buy-ins are a potentially powerful tool, because they blunt opposition to reform by allowing people with good employer-provided insurance to keep it, while expanding the role of public insurance. And in the likely event that employer-provided insurance becomes less affordable, the availability of a public option will allow for a gradual transition. And a public option would also make insurance markets that remain better for customers.

I don't mean to understate the political challenges facing health-care reformers. Making the political case for Medicare for all is very doable, but enacting it — or even a major transitional step — won't be easy. Vested interests who oppose a primarily or exclusively public insurance system are aware of the potential power of a public option too.

But what's politically possible at a given point is a question that can be answered the next time the Democrats take over the White House and Congress. In the meantime, the Democratic Party needs to establish Medicare for all or a comparable universal program as a goal — and whether it's Gillibrand, Sanders, or another candidate, this is almost certainly the direction the next Democratic nominee will be pushing in.